• 제목, 요약, 키워드: Optimal design

검색결과 9,052건 처리시간 0.056초

프리스트레스트 콘크리트 박스 거더 교량의 최적 설계에 관한 연구 (A Study on the Optimal Design of Prestressed Concrete Box Girder Bridges)

  • 노금래;윤희택;박선규
    • 한국콘크리트학회:학술대회논문집
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    • pp.251-256
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    • 1999
  • In the preliminary design stage of Prestressed Concrete (PSC) Box Girder Bridges, the design factors(including depth, thickness of web, and jacking force) decided by inexperience designer could heavily affect the final design factors. So there is a possibility that the design ends up with an excessively wasteful design. To aim at an economical design with preventing an excessive design, the optimal design program has been developed by using ADS optimal program and SPCFRAME(PSC Bridge analysis program) in these studies. The optimal design program automatically calculates economically optimized design studies. The optimal design program automatically calculates economically optimized design factors by introducing the optimal design techniques of PSC box girder bridge design. The objective function for optimal design is material cost of box girder and constrained functions are constituted with design specifications and workability. The optimal design techniques used the Sequential Unconstraint Minimization Technique (SUMT) with performing the optimal design program. In this study, We designed unprismatic section bridge and prismatic section bridge in the same design condition by optimal design program developed in this study. By analyzing the results we suggested the practical form of tendon's layout comparing the optimal desingns on the basis of each tendon's layout.

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CFD 연성해석과 유전자 알고리즘을 이용한 실내 열환경 최적설계에 관한 연구 (Optimal Design for Indoor Thermal Environment based on CFD Simulation and Genetic Algorithms)

  • 김태연;이윤규
    • 설비공학논문집
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    • v.16 no.2
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    • pp.111-120
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    • 2004
  • The optimal design method of indoor thermal environment using CFD coupled simulation and genetic algorithms (GA) is developed in this study. CFD could analyze the thermal environment considering the distribution of temperature, velocity, etc. in a room. Therefore, It would be appropriate to use CFD for the optimal design method considering their distribution. In this paper, the optimal design means the most appropriate boundary conditions of the room among the conditions where the design target of indoor therm environment is achieved. Two step optimal indoor thermal environment design method is proposed. It includes the GA for searching the optimal indoor thermal environment design. To examine the performance of this method, the optimal design of hybrid ventilation system, which uses the natural cross ventilation and the radiation-cooling panel is conducted. The optimal design which satisfies the design target (thermal comfort, minimum cooling load, minimum vertical temperature difference) is found using two step optimal design method.

D-Optimal 반응표면모델에 의한 섀시 프레임 최적설치 (Optimization of Chassis Frame by Using D-Optimal Response Surface Model)

  • 이광기;구자겸;이태희
    • 대한기계학회논문집A
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    • v.24 no.4
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    • pp.894-900
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    • 2000
  • Optimization of chassis frame is performed according to the minimization of eleven responses representing one total frame weight, three natural frequencies and seven strength limits of chassis frame that are analyzed by using each response surface model from D-optimal design of experiments. After each response surface model is constructed form D-optimal design and random orthogonal array, the main effect and sensitivity analyses are successfully carried out by using this approximated regression model and the optimal solutions are obtained by using a nonlinear programming method. The response surface models and the optimization algorithms are used together to obtain the optimal design of chassis frame. The eleven-polynomial response surface models of the thirteen frame members (design factors) are constructed by using D-optimal Design and the multi-disciplinary design optimization is also performed by applying dual response analysis.

스템핑 공정 최적화 시스템의 개발 : 최적블랭크 설계와 최적배치의 일체화 (Development of Stamping Process Optimization System: Integration of Optimal Blank Design and Optimal Nesting)

  • 심현보;이상헌;박종규;김흥업
    • 한국소성가공학회:학술대회논문집
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    • pp.283-287
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    • 2003
  • In recent years, design of an optimal blank shape is very important for sheet metal forming process in the automobile industry because the raw material cost rate is significant part in the automobile industry. With the design of an optimal blank shape, the engineer can protect a blank from an excessive holding force to improve the quality and reduce the ratio of material scrap. Therefore design of an optimal blank shape is inevitable in sheet metal forming process. However, if it causes a complicated shape of blank, it may be difficult to do the blank layout optimally. In this study, we developed software of optimal blank layout connected with the software of optimal blank shape design which was created in the past by the present authors. And by using these softwares, we would like to present the method in order to get optimal utilization ratio easily and precisely within short time for the sequence of works from design to blank layout.

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차량 충돌 해석을 통한 중앙분리대의 최적 성능 설계 (Optimal Performance Design for Concrete Median Barrier with Crashworthiness Analysis)

  • 한석영;고성호;최형연
    • 한국자동차공학회논문집
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    • v.10 no.1
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    • pp.168-178
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    • 2002
  • The purpose of this study is to develop an optimal performance design ova concrete median barrier using the design of experiment and crash simulation which is done by Pam-Crash, one of the commercial crash simulation software. A formula of characteristic value was suggested to obtain an optimal performance design considering all of von Mises stress, volume and acceleration at center of gravity of a heavy truck. An optimal design of a concrete median barrier was obtained by the analysis of variance based on design of experiment and crash simulation. A crash simulation with the optimal design was accomplished in order to verify the suitability of the suggested formula and the proper application of the design of experiment. The obtained optimal design was satisfied for a domestic design regulation of a concrete median barrier.

블랭크 설계와 배치의 일체화를 통한 스탬핑 공정 최적화 시스템의 개발 (Development of Stamping Process Optimization System through the Integration of Blank Design and Nesting)

  • 심현보;박종규
    • 소성가공
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    • v.12 no.7
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    • pp.615-622
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    • 2003
  • In the automobile industry, the design of optimal blank shape becomes a significant part of the stamping. It provides many evident advantages, sush as enhancement of formability, reduction of material cost and product development period. However, the nesting process, required for the optimal usage of materials in the blanking becomes more complicated as the blank shape becomes complicated, like most optimal blank shape. In this study, stamping process optimization system for the optimal usage of material has been developed through the integration of optimal blank design and optimal nesting. For optimal blank design, a radius vector method, the modified version of the initial nodal velocity method, the past work of the present author, have been proposed. Both the optimal blank design and optimal nesting programs have been developed under the GUI environment for the convenience of engineers. The efficiency of the optimization system has been verified with some chosen problems.

Optimal Structural Design for Flexible Space Structure with Control System Based on LMI

  • Park, Jung-Hyen;Cho, Kyeum-Rae
    • Journal of Mechanical Science and Technology
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    • v.16 no.1
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    • pp.75-82
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    • 2002
  • A simultaneous optimal design problem of structural and control systems is discussed by taking a 3-D truss structure as an object. We use descriptor forms for a controlled object and a generalized plant because the structural parameters appear naturally in these forms. We consider a minimum weight design problem for structural system and disturbance suppression problem for the control system. The structural objective function is the structural weight and the control objective function is $H_{\infty}$ norm from the disturbance input to the controlled output in the closed-loop system. The design variables are cross sectional areas of the truss members. The conditions for the existence of controller are expressed in terms of linear matrix inequalities (LMI) By minimizing the linear sum of the normalized structural objective function and control objective function, it is possible to make optimal design by which the balance of the structural weight and the control performance is taken. We showed in this paper the validity of simultaneous optimal design of structural and control systems.

Augmented D-Optimal Design for Effective Response Surface Modeling and Optimization

  • Kim, Min-Soo;Hong, Kyung-Jin;Park, Dong-Hoon
    • Journal of Mechanical Science and Technology
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    • v.16 no.2
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    • pp.203-210
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    • 2002
  • For effective response surface modeling during sequential approximate optimization (SAO), the normalized and the augmented D-optimality criteria are presented. The normalized D-optimality criterion uses the normalized Fisher information matrix by its diagonal terms in order to obtain a balance among the linear-order and higher-order terms. Then, it is augmented to directly include other experimental designs or the pre-sampled designs. This augmentation enables the trust region managed sequential approximate optimization to directly use the pre-sampled designs in the overlapped trust regions in constructing the new response surface models. In order to show the effectiveness of the normalized and the augmented D-optimality criteria, following two comparisons are performed. First, the information surface of the normalized D-optimal design is compared with those of the original D-optimal design. Second, a trust-region managed sequential approximate optimizer having three D-optimal designs is developed and three design problems are solved. These comparisons show that the normalized D-optimal design gives more rotatable designs than the original D-optimal design, and the augmented D-optimal design can reduce the number of analyses by 30% - 40% than the original D-optimal design.

프리스트레스트 콘크리트 박스 거더 교량의 최적설계에 관한 연구 (A Study on the Optimal Design of Prestressed Concrete Box Girder Bridges)

  • 노금래;윤희택;박선규
    • 한국구조물진단유지관리공학회 논문집
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    • v.4 no.2
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    • pp.139-149
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    • 2000
  • In the preliminary design stage of prestressed concrete (PSC) box girder bridges, the design factors decided by inexperience designer could heavily affect to the results of final design. There is a possibility that the design ends up with an excessively wasteful design. To achieve an economical design with preventing an excessive design, the optimal design technique has been developed using ADS optimal program and SPCFRAME in this study. The objective function for the optimal design problem is the material cost of box girders and constrained functions are constituted with design specifications and workability. The Sequential Unconstraint Minimization Technique (SUMT) is used for the optimal design in this study. We designed an uniform cross-section bridge and an ununiform cross-section bridge in the same design condition by optimal design technique developed in this study. Analyzing the results obtained for various tendon layouts, we suggest a standard tendon layout which gives the most effective structural behavior.

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유전자 알고리즘을 이용한 닐센아치교의 최적설계기법 (Opitmal Design Technique of Nielsen Arch Bridges by Using Genetic Algorithm)

  • 이광수;정영수
    • 한국강구조학회 논문집
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    • v.21 no.4
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    • pp.361-373
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    • 2009
  • 유전자 알고리즘을 이용한 닐센아치교의 최적설계기법을 이 논문에서 제시하였다. 설계 매개변수로는 닐센아치교의 아치-라이즈비와 강중비에 대해서 최적화기법을 적용하여 각각의 거동을 분석하고, 적정성을 평가하여 최적의 매개변수 값을 결정하였다. 매개변수의 결정은 구조물의 안전성과 사용성 그리고 경제성에 중요한 설계인자로서 정형화가 요구된다. 이를 위해 최적화 기법으로 전역 최적해 탐색능력이 우수한 유전자 알고리즘을 사용하였으며, 설계 목적함수로는 구조물의 총 중량을 사용하였고, 제약조건으로는 변위, 응력, 시공성 제약조건을 두었다. 구조해석은 미소변위이론에 의한 탄성해석을 수행하여 유전자 알고리즘과 조합하여 병렬연산으로 수행시간을 단축시켰다. 이 연구에서 개발된 최적설계기법을 사용하여 최적의 아치-라이즈비와 강중비, 최적설계영역을 제시 하였으며 실무에 적용할 수 있도록 하였다.